Androgen-regulated epididymal secretory proteins associated with post-testicular sperm development

Identification and characterisation of the epididymal proteins in the lizard, Eutropis carinata (Reptilia, Squamata) (Schneider, 1801)

Lizards are seasonal breeders. Cyclic reproductive nature makes lizard as a useful model for the study of the reproductively active protein secretions in the epididymis. During breeding season, the epididymides of the lizard secret proteins that mixes with the spermatozoa and create a favourable environment for sperm maturation. In this spectrum, the aim of this study is to identify and characterize proteins which are present in the lumen of the epididymis of the lizard, E. carinata during the active phase of reproduction. The identification and analysis of the proteins are done through the proteomic approaches. The epididymal luminal fluid sample was taken from the reproductively active and inactive phase and these are subjected to the size exclusion chromatography. Two major peaks (peak 1 and peak 2) were obtained in the epididymal luminal fluid sample taken during the reproductively active phase. On the other hand, the sample from the reproductively inactive phase showed one peak (peak 1) whereas, peak 2 is not present during this phase. The peak 2 belong to reproductively active phase was later subjected to the proteomic analysis. Appropriate gel electrophoresis separation and purification methods are combined with LC-MS/MS in order to identify and characterize the proteins that are presented during the reproductively active phase. Further, in this work, nine proteins are identified including three enzymes and three heat shock proteins. Among the identified proteins, bioinformatics analysis predicts that majority of them are localized in the cytoplasm. In addition to this, an observation is made in the endoplasmic reticulum where it is seen that a close protein-protein interaction network of three molecular chaperones are involved in protein processing. Overall, this paper opens up a new dimension search for epididymal markers for the first time in reptiles, particularly lizards.

Albumin is synthesized in epididymis and aggregates in a high molecular mass glycoprotein complex involved in sperm-egg fertilization

The epididymis has an important role in the maturation of sperm for fertilization, but little is known about the epididymal molecules involved in sperm modifications during this process. We have previously described the expression pattern for an antigen in epididymal epithelial cells that reacts with the monoclonal antibody (mAb) TRA 54. Immunohistochemical and immunoblotting analyses suggest that the epitope of the epididymal antigen probably involves a sugar moiety that is released into the epididymal lumen in an androgen-dependent manner and subsequently binds to luminal sperm. Using column chromatography, SDS-PAGE with insitu digestion and mass spectrometry, we have identified the protein recognized by mAb TRA 54 in mouse epididymal epithelial cells. The ∼65 kDa protein is part of a high molecular mass complex (∼260 kDa) that is also present in the sperm acrosomal vesicle and is completely released after the acrosomal reaction. The amino acid sequence of the protein corresponded to that of albumin. Immunoprecipitates with anti-albumin antibody contained the antigen recognized by mAb TRA 54, indicating that the epididymal molecule recognized by mAb TRA 54 is albumin. RT-PCR detected albumin mRNA in the epididymis and fertilization assays invitro showed that the glycoprotein complex containing albumin was involved in the ability of sperm to recognize and penetrate the egg zona pellucida. Together, these results indicate that epididymal-derived albumin participates in the formation of a high molecular mass glycoprotein complex that has an important role in egg fertilization.

Cysteine-rich secretory protein-3 (CRISP3) is strongly up-regulated in prostate carcinomas with the TMPRSS2-ERG fusion gene

A large percentage of prostate cancers harbor TMPRSS2-ERG gene fusions, leading to aberrant overexpression of the transcription factor ERG. The target genes deregulated by this rearrangement, however, remain mostly unknown. To address this subject we performed genome-wide mRNA expression analysis on 6 non-malignant prostate samples and 24 prostate carcinomas with (n = 16) and without (n = 8) TMPRSS2-ERG fusion as determined by FISH. The top-most differentially expressed genes and their associations with ERG over-expression were technically validated by quantitative real-time PCR and biologically validated in an independent series of 200 prostate carcinomas. Several genes encoding metabolic enzymes or extracellular/transmembrane proteins involved in cell adhesion, matrix remodeling and signal transduction pathways were found to be co-expressed with ERG. Within those significantly over-expressed in fusion-positive carcinomas, CRISP3 showed more than a 50-fold increase when compared to fusion-negative carcinomas, whose expression levels were in turn similar to that of non-malignant samples. In the independent validation series, ERG and CRISP3 mRNA levels were strongly correlated (r_s = 0.65, p<0.001) and both were associated with pT3 disease staging. Furthermore, immunohistochemistry results showed CRISP3 protein overexpression in 63% of the carcinomas and chromatin immunoprecipitation with an anti-ERG antibody showed that CRISP3 is a direct target of the transcription factor ERG. We conclude that ERG rearrangement is associated with significant expression alterations in genes involved in critical cellular pathways that define a subset of locally advanced PCa. In particular, we show that CRISP3 is a direct target of ERG that is strongly overexpressed in PCa with the TMPRSS2-ERG fusion gene.

Identification and characterization of an epididymis-specific gene, Ces7

Carboxylesterases (CEs) represent a multigene family of serine-dependent enzymes. Male-dependent CEs are over-expressed in the male reproductive tract of different animal species (bivalve mollusks, fruit-flies, and mammals). Here, a novel rat epididymis-specific gene named Ces7 was cloned and characterized. It was a novel member of CE family, which was mainly expressed and secreted to the lumens of the corpus and cauda epididymis. CES7 protein was highly glycosylated as other mammalian CEs. Furthermore, Ces7 increased with age growth until sex maturation and then maintained at high level. CES7 might be one of the major CEs in male reproductive tract and contribute to the sperm fertilization.

Molecular biology of sperm maturation in the human epididymis

Male infertility is a frequent cause of childlessness, and, indeed, a comparison of the contributions to conception failure made by male and female factors shows them to be equally frequent. In practice, male infertility appears to be resistant to most treatments. However, the major reason for this may be that often attempts are carried out without knowing the cause of the problem. Unlike in women, obstructions and hormonal disorders are rare in male infertility. Rather, it would appear that sperm disorders are the most common cause, reflecting a variety of pathogenetic mechanisms. Defects in sperm morphology, defective sperm movement, deficient development or functional failure of the acrosome, and the excessive generation of reactive oxygen species are changes that are often seen in infertile semen, but little is known about their aetiology. In 5–10% of men being treated for infertilty, an autoimmune reaction against spermatozoa is observed. Although the correlation between the presence of systemic antisperm antibodies and fertility potential is poor, the appearance of sperm-bound antibodies of immunoglobulin class IgA in semen seems to be closely associated with infertility. Studies in laboratory animals and humans have shown that complementary adhesion molecules are located on the surface of oocytes and spermatozoa. These molecules interact and lead to gamete fusion. Abnormalities in these molecules on the sperm surface might be expected to contribute to male infertility. However, their clinical significance has not yet been documented, and the molecular basis of human gamete interaction is far from being understood. Therefore, the key to understanding male infertility may lie in basic research which directly targets the fundamental cellular and molecular biology of the human spermatozoon.

Cloning and identification of a novel sperm binding protein, HEL-75, with antibacterial activity and expressed in the human epididymis

BACKGROUND

The HEL-75 protein is a beta-defensin that was identified by analyzing a human epididymis cDNA library. Studying its function may not only elucidate the mechanisms of host defense, but may also provide new alternatives for novel therapeutic drugs for reproductive tract infections.

METHODS

The HEL-75 gene was amplified by PCR, and its structure and function were predicted and analyzed with bioinformatics tools. Polyclonal serum was raised against recombinant HEL (rHEL)-75 protein. The gene expression pattern was analyzed with RT-PCR and immunofluorescent staining. Finally, the antimicrobial activity and function during fertilization of HEL-75 were analyzed using a colony-forming unit assay and IVF, respectively.

RESULTS

The human HEL-75 gene is located on chromosome 20p13 and encodes a 95 amino acid protein with a predicted N-terminal signal peptide of 22 amino acids. The protein has six conserved cysteine residues, characteristic of members of the beta-defensin superfamily, as well as several potential post-translational modification sites. At the transcriptional level, HEL-75 was expressed in the epididymis and lung, but only in the epididymis at the translational level. Immunofluorescent staining showed that HEL-75 protein bound spermatozoa in the epididymis. RHEL-75 protein could kill Escherichia coli in vitro in a dose- and time-dependent fashion. However, no effect was observed on sperm motility nor fertilization when spermatozoa were blocked with anti-rHEL-75 polyclonal serum.

CONCLUSION

HEL-75 is a new beta-defensin expressed in the epididymis and on sperm; it may play an important role in host defense.

Identification and isolation of boar sperm specific antigens with potential role in sperm-egg interaction

Investigations on specific and functionally active sperm antigens would bring about the elucidation of the mechanisms of gamete interaction and help the search to new approaches for prognosis and regulation of fertility. Previously, we have produced a polyclonal rabbit anti-boar spermatozoa antibody (RABSA) that might affect the fertilizing capacity of boar spermatozoa. The sperm specificity of RABSA was demonstrated by double immunodiffusion, immunoelectrophoresis and ELISA against boar spermatozoa, as well as against saline extracts of boar reproductive and somatic organs. Using indirect immunofluorescence (IIF) test, here we provide evidence that RABSA stained the acrosomes of ejaculated and capacitated boar and human spermatozoa, the fluorescence being intensified on the equatorial region after the acrosome reaction. The RABSA cognate antigen/s is a subject of interest because of their specific localization in sperm structures, which is shown to be a binding and/or fusion competence region. Using ion-exchange (Heparin-Sepharose) chromatography, we eluted an antigen with molecular mass 60 kDa (Ag60) in SDS-PAGE from NP40 extracts of capacitated boar spermatozoa. In Western blot, RABSA recognized specifically this antigen. The Ag60 did not affect the sperm-ligand activity of zona pellucida in a porcine sperm-zona binding assay. IIF experiments showed that zona-free porcine oocytes preincubated with Ag60 and RABSA presented fluorescent labeling over the entire egg surface. The biological and IIF experiments provide evidence supporting the involvement of Ag60 in functional steps required for sperm-egg binding and/or fusion, but not sperm-zona pellucida binding.

Seasonal timing of sperm production in roe deer: interrelationship among changes in ejaculate parameters, morphology and function of testis and accessory glands

Roe deer are seasonal breeders with a short rutting season from mid-July to mid-August. The seasonality of reproductive activity in males is associated with cyclic changes between growth and involution of both testes and the accessory sex glands. This study characterizes morphological and functional parameters of these organs prior to, during and after breeding season in live adult roe deer bucks. Size and morphology of the reproductive tract was monitored monthly by transcutaneous (testes, epididymis) and transrectal (accessory glands) ultrasonography. Semen was collected by electroejaculation. Concentration, motility and morphological integrity of spermatozoa as well as the content of proteins and testosterone in semen plasma were evaluated. Proportions of haploid, diploid and tetraploid cells were estimated by flow cytometry in testicular tissue biopsies. Serum testosterone was measured by enzyme immunoassay. Most parts of the male reproductive tract showed distinct circannual changes in size and texture. These changes were most pronounced in the testes, seminal vesicles, and prostate. All reproductive organs were highly developed during the rut only. The volume of ejaculates, total sperm number and percentages of motile and intact spermatozoa also showed a maximum during this period and corresponded with high proportions of haploid cells in the testis. The highest percentages of tetraploid cells were found in the prerutting period. The production of motile and intact spermatozoa correlated with both the protein content of semen plasma and the concentration of testosterone in semen plasma and blood serum. These results suggest the importance of combined actions of the testes and accessory sex glands and the crucial role of testosterone in facilitating the optimal timing of intensified semen production to ensure sufficient numbers of normal spermatozoa in seasonal breeders.

Abdominal temperature induces region-specific p53-independent apoptosis in the cauda epididymidis of the mouse

It is widely accepted that temperature regulates gene expression and function in the epididymis. However, the significance of reduced temperature of the scrotum in cell survival had not often been examined. Our hypothesis was that the experimental increase of the temperature could induce apoptosis. Using a surgical method that consists of surgically reflecting the cauda epididymidis in the abdomen, we have been able to show that this is the case. Apoptosis was examined by histologic procedures and by visualization of DNA fragmentation in agarose gels. We determined that the apoptosis is region-specific and affects only the principal cells of the proximal region of the cauda. It starts 12 h after surgery and ends by the third day. The apoptotic cells are eliminated by extrusion into the lumen and phagocytosis by adjacent cells. The complete molecular mechanism of apoptosis in this case remains unknown, but we have used the techniques of immunocytochemistry, Western blot, and reverse transcription-polymerase chain reaction to determine the role of some molecules. We have seen no significant role of androgens, the tumor suppressor p53, nor two heat shock proteins, hsp-25 and hsp-70. Nevertheless, we have detected a strong induction of bax and bcl-2 gene products. While the former should be responsible for the apoptosis observed, the latter would promote the survival of most of the cells of the cauda epididymis.

Effect of vasectomy on gene expression in the epididymis of cynomolgus monkey

Vasectomy has been shown to affect the pattern of mRNA expression of P34H, a human sperm protein added to the acrosomal cap during epididymal transit. It has been reported that vasectomy alters the histology of the reproductive tract in various species as a result of the increased pressure in the epididymis. The aim of this study was to evaluate if other epididymis-specific mRNAs, which are expressed in different patterns along the duct, are altered by vasectomy as well. We analyzed the expression of P31m (a monkey homologue of human P34H) and three different HE-like (HE-l) mRNAs along the epididymis in the cynomolgus monkey (Macaca fascicularis). Sexually mature cynomolgus monkeys were vasectomized unilaterally; then the epididymides were surgically removed at different time points. The ipsilateral normal epididymis was used as a control. Histomorphometric measurements showed that the height of the epididymal epithelial cells started to be affected only at 14 wk postsurgery. However, Northern blot and in situ hybridization analysis showed that the expression pattern of P31m, HE1, and HE5-like mRNA along the epididymis was not affected by vasectomy. Only the HE2-like mRNA predominantly expressed in the normal corpus epididymidis was significantly lowered 14 wk after vasectomy. Thus, ductal obstruction differentially alters mRNA expression along the epididymis of the cynomolgus monkey.

A comparative analysis of expression and processing of the rat epididymal fluid and sperm-bound forms of proteins D and E

The mammalian epididymis secretes numerous proteins important for sperm maturation. Among these are proteins D and E, which belong to the CRISP family (cysteine-rich secretory proteins) and are the product of the Crisp-1 gene. These proteins have been the focus of a number of studies and have been implicated in sperm/egg fusion. Protein D and protein E have been purified to apparent homogeneity in several laboratories. Polyclonal antibodies raised against each protein typically cross-reacted with both proteins, suggesting that they were immunologically similar, if not identical. Our laboratory has previously reported the generation of a monoclonal antibody (mAb 4E9) that recognizes only protein E. Using mAb 4E9, the localization of protein E was shown to be domain specific on the sperm surface and there is processing of the protein in the fluid, with only the lowest molecular weight form associating with sperm. Subsequent purification and amino acid sequencing of protein D confirmed that proteins D and E are nearly identical and differ only by presence of the 4E9 epitope on protein E. Here we report the generation of antibodies to regions of amino acid sequence identity in proteins D and E. Using these antibodies, we demonstrate that protein D associates with the sperm head and that a portion of this protein may be proteolytically processed. In addition, we demonstrate that the proteolytic processing of protein E occurs in the carboxy terminal region of this protein. The data also suggest that a portion of protein D may also undergo processing, similar to that of protein E. Finally, we use these antibodies to demonstrate that proteins D and E are differentially expressed by the epididymal epithelium. Taken together, these data suggest that proteins D and E may have individual roles in sperm function.

On the regulation of Crisp-1 mRNA expression and protein secretion by luminal factors presented in vivo by microperfusion of the rat proximal caput epididymidis

Synthesis and secretion of certain epididymal proteins are regulated by lumicrine factors from the testis or from upstream regions of the excurrent ducts. Cysteine-rich secreted protein-1 (Crisp-1) is a major androgen regulated protein in the epididymal lumen fluid of the rat and other species. Previous research has demonstrated that disturbance of the luminal microenvironment through obstruction of the tract reduces Crisp-1 synthesis and secretion. The present study was undertaken to determine the influence of the luminal microenvironment on rat proximal caput epididymal Crisp-1 secretion into lumen fluid and on Crisp-1 gene expression in the same tubules. Western blot analysis demonstrated that Crisp-1 protein concentrations were reduced from control levels by perfusion with artificial caput fluid containing no testicular factors and were not increased by perfusion with fluids containing rete testis fluid proteins. Crisp-1gene expression was also reduced by perfusion with artificial caput fluid and not increased by perfusion with rete testis fluid proteins. Perfusion with artificial caput fluid containing 5alpha-dihydrotestosterone did increase one Crisp-1 transcript. This study demonstrates that intraluminal testicular proteins are not important co-regulators with androgens of Crisp-1gene expression or resulting Crisp-1 secretion into the rat proximal caput tubule lumen in vivo.

Nongenomic effect of testosterone on chloride secretion in cultured rat efferent duct epithelia

Short-circuit current (I(sc)) technique was used to investigate the role of testosterone in the regulation of chloride secretion in cultured rat efferent duct epithelia. Among the steroids tested, only testosterone, and to a lesser extent, 5alpha-dihydrotestosterone (5alpha-DHT), reduced the basal and forskolin-induced I(sc) in cultured rat efferent duct epithelia when added to the apical bathing solution. Indomethacin, a 3alpha-hydroxysteroid dehydrogenase, did not affect the inhibitory effect of 5alpha-DHT. The effect of testosterone occurred within 10-20 s upon application and was dose dependent with apparent IC(50) value of 1 microM. The effect was abolished by removal of Cl(-) but not HCO from the normal Krebs-Henseleit solution, suggesting that testosterone mainly inhibited Cl(-) secretion. The efferent duct was found to be most sensitive to testosterone, while the caput and the cauda epididymidis were only mildly sensitive. Cyproterone acetate, a steroidal antiandrogen, or flutamide, a nonsteroidal antiandrogen, did not block the effect of testosterone on the forskolin-induced I(sc), nor did protein synthesis inhibitors, cycloheximide, or actinomycin D. However, pertussis toxin, a G(i) protein inhibitor, attenuated the inhibition of forskolin-induced I(sc) by testosterone. Testosterone caused a dose-dependent inhibition of forskolin-induced rise in cAMP in efferent duct cells. It is suggested that the rapid effect of testosterone was mediated through a membrane receptor that is negatively coupled to adenylate cyclase via G(i) protein. The role of nongenomic action of testosterone in the regulation of electrolyte and fluid transport in the efferent duct is discussed.

Androgen receptor signalling: comparative analysis of androgen response elements and implication of heat-shock protein 90 and 14-3-3eta

Androgen receptor (AR) signalling was analysed using as models the cysteine-rich secretory protein-1 (CRISP-1) and CRISP-3 gene promoters, which are differentially regulated by androgen in vivo and contain multiple potential androgen response elements. Using electrophoretic mobility shift assay, we identified several elements with differing affinities for the AR at positions -3706, -1270, -1253 and -350 of the CRISP-1 promoter and at positions -369 and -349 of the CRISP-3 promoter. The strongest binding was observed for the -1253 element of CRISP-1. In transactivation assays using a PC-3 cell line stably transfected with the AR (PC-3/AR), the -1253 element placed as two or four copies upstream of the TK minimal promoter yielded a strong induction of luciferase reporter gene activity in the presence of the androgen methyltrienolone (R1881). In the context of the CRISP promoters a 2-fold induction by R1881 was measured for the CRISP-3 upstream region whereas only limited effects were noted for the CRISP-1 upstream region. The androgenic stimulation of the p(-1253 ARE)(4x)-TK-luciferase reporter construct was dose-dependently inhibited by geldanamycin and radicicol, two compounds that selectively interact with the chaperone protein, heat-shock protein 90. Cotransfection with an expression vector for the 14-3-3eta protein markedly enhanced the androgen-dependent stimulation. These results emphasize the influence of promoter context on androgen regulation and the importance of AR-associated proteins.

Mammalian sperm-egg fusion: evidence that epididymal protein DE plays a role in mouse gamete fusion

Rat epididymal protein DE associates with the sperm surface during epididymal maturation and is a candidate molecule for mediating gamete membrane fusion in the rat. Here, we provide evidence supporting a role for DE in mouse sperm-egg fusion. Western blot studies indicated that the antibody against rat protein DE can recognize the mouse homologue in both epididymal tissue and sperm extracts. Indirect immunofluorescence studies using this antibody localized the protein on the dorsal region of the acrosome. Experiments in which zona-free mouse eggs were coincubated with mouse capacitated sperm in the presence of DE showed a significant and concentration-dependent inhibition in the percentage of penetrated eggs, with no effect on either the percentage of oocytes with bound sperm or the number of sperm bound per egg. Immunofluorescence experiments revealed specific DE-binding sites on the fusogenic region of mouse eggs. Because mouse sperm can penetrate zona-free rat eggs, the participation of DE in this interaction was also investigated. The presence of the protein during gamete coincubation produced a significant reduction in the percentage of penetrated eggs, without affecting the binding of sperm to the oolemma. These observations support the involvement of DE in an event subsequent to sperm-egg binding and leading to fusion in both homologous (mouse-mouse) and heterologous (mouse-rat) sperm-egg interaction. The lack of disintegrin domains in DE indicates that the protein interacts with its egg-binding sites through a novel mechanism that does not involve the reported disintegrin-integrin interaction.

Antisperm antibodies associated with infertility: properties and encoding genes of target antigens

Infertility among couples of reproductive age is a perplexing condition when the cause is indeterminate. These cases are classified as unexplained infertility. In a subset of subjects, antisperm antibodies with sperm agglutinating and/or immobilizing activities have been detected in the blood or fluids of the reproductive tract. These cases are designated as immunologic infertility although a cause and effect relationship of the antibodies to infertility has not been established. In this review, seven target sperm antigens to antibodies associated with infertility and their encoding genes are described. The antisperm antibodies (ASAs) examined were obtained from infertile women or were monoclonal antibodies (mAb) raised against human sperm proteins. All the ASAs studied possessed potent sperm agglutinating and/or immobilizing activities. The target antigens were isolated from human and other mammalian sperm, and the encoding genes identified. The seven antigens are YWK-II, BE-20, rSMP-B, BS-63 (nucleoporin-related), BS-17 (calpastatin), HED-2 (zyxin), and 75- kDa. Each antigen is a distinct and separate entity and is produced by different cells of the reproductive tract, (e.g., germ cells, epididymal epithelial cells, and Sertoli cells). No single predominant target component has been found to interact with the ASAs. It is proposed that immunologic infertility is the consequence of the combined actions of multiple ASAs in immobilizing and/or agglutinating spermatozoa, blocking spermegg interaction, preventing implantation, and/or arresting embryo development.

Relationship between the association of rat epididymal protein "DE" with spermatozoa and the behavior and function of the protein

Rat epididymal glycoprotein DE associates with the dorsal region of the sperm head during sperm maturation, migrates to the equatorial segment (ES) with the acrosome reaction (AR), and is involved in gamete membrane fusion. In the present study we examined the association of DE with the sperm surface and the relationship of this interaction with the behavior and function of the protein. Cloning and sequencing of DE revealed a lack of hydrophobic domains and the presence of 16 cysteine residues in the molecule. Experiments in which cauda epididymal sperm were subjected to different extraction procedures indicated that while most of the protein is removable from sperm by mild ionic strength, a low amount of DE, resistant to even 2 M NaCl, can be completely extracted by agents that remove integral proteins. However, the lack of hydrophobic domains in the molecule and the failure of DE to interact with liposomes, does not support a direct insertion of the protein into the lipid bilayer. These results, and the complete extraction of the tightly bound protein by dithiothreitol, suggest that this population would correspond to a peripheral protein bound to a membrane component by strong noncovalent interactions that involve disulfide bonds. While ELISA experiments showed that no protein could be extracted by NaCl from capacitated sperm, indirect immunofluorescence studies revealed the ability of the NaCl-resistant protein to migrate to the ES. Together, these results support the existence of two populations of DE: a major, loosely bound population that is released during capacitation, and a minor strongly bound population that remains after capacitation, migrates to the ES with the AR, and thus would correspond to the one with a role in gamete fusion.

Identification of differentially expressed genes in dorsal root ganglia following partial sciatic nerve injury

Partial sciatic nerve injury, a model of neuropathic pain, elicits a variety of neurochemical, electrophysiological and neuroanatomical changes in primary sensory neurons. We have used the technique of messenger RNA differential display to identify genes with altered expression in these neurons which may contribute to the development of aberrant sensation following such peripheral nerve damage. This approach identified 14 distinct complementary DNA clones, representing transcripts with increased ipsilateral expression in L4/5 dorsal root ganglia, two weeks after unilateral partial ligation of the rat sciatic nerve. Both Zucker diabetic fatty rats and their lean counterparts were used in this study but none of the transcripts identified showed an induction that was confined to one of the two groups. The majority of the clones did not show significant sequence similarity to previously reported genes and therefore may represent novel messenger RNA sequences or, alternatively, unknown regions of partially characterised messenger RNAs. Two of the clones represented transcripts for the known proteins muscle LIM protein and acidic epididymal glycoprotein, neither of which had previously been associated with expression in the nervous system. Reverse transcriptase-polymerase chain reaction analysis and in situ hybridization confirmed that the messenger RNA expression of both muscle LIM protein and acidic epididymal glycoprotein was induced in an ipsilateral-specific manner. Their localisations, examined with in situ hybridization in L5 dorsal root ganglia, were limited in each case to a sub-population of neuronal profiles. Those neuronal profiles that demonstrated muscle LIM protein hybridization were distributed across the profile size range, whereas the distribution of acidic epididymal glycoprotein-positive profiles appeared to be skewed towards smaller profiles. The induction of muscle LIM protein and acidic epididymal glycoprotein in dorsal root ganglia may play an important functional role in the adaptive response of primary sensory neurons following partial sciatic nerve injury.

Gene expression in the epididymis

The epididymis is a tubular organ exhibiting vectorial functions of sperm concentration, maturation, transport, and storage. The molecular basis for these functions is poorly understood. However, it has become increasingly clear that regional differences along the length of the duct play a role in epididymal physiology and that region-specific gene expression is involved in the formation of these differences. Although not an overtly segmented organ, the epididymis consists of a series of highly coiled "zones," separated by connective tissue septulae and distinct by cell morphology and their pattern of gene expression. Thus, it constitutes an interesting mammalian model to study how pattern formation is achieved by differential gene activity. A large number of epididymis-expressed genes have been cloned and analyzed at the molecular level, most of them have been characterized by a distinct temporal and spatial expression pattern within the organ. Only recently have theories been developed about how and when during ontogenesis this pattern formation takes place and what its significance might be. This review summarizes the current knowledge on regionalized gene expression in the epididymis and presents hypotheses concerning its ontogenetic origin and regulation in the adult.

Expression of transcripts for cysteine-rich secretory proteins (CRISPs) in the murine lacrimal gland

Cysteine-rich secretory proteins (CRISPs) represent a family of evolutionarily conserved proteins which may play a role in the innate immune system and are transcriptionally regulated by androgens in several tissues. Transcripts for all three members of the CRISP family have now been identified in the murine lacrimal gland. RT-PCR using primers able to discriminate between the related CRISP forms allowed the amplification of fragments with the expected length. DNA sequencing revealed a complete identity with the hitherto characterized epididymal CRISP-1, testicular CRISP-2, and salivary gland CRISP-3. An analysis of several mouse strains indicated that all expressed the three CRISP forms, but in differing amounts. RT-PCR analysis of RNA isolated from acinar cells of lacrimal glands revealed that they expressed CRISP-1 and CRISP-2. Semiquantitative and quantitative analyses furthermore showed higher CRISP-1 and CRISP-3 mRNA levels in the lacrimal glands of male BALB/c and NOD mice when compared to females. Testosterone treatment of C3H/HeJ female mice was followed by an upregulation of the steady-state CRISP-1 but not CRISP-2 transcript levels. A comparable stimulation was observed for the mRNAs coding for parotid secretory protein (PSP), a factor previously shown to exhibit sexual dimorphism in the murine lacrimal gland. The expression of CRISP transcripts in the lacrimal gland is consistent with a function in the innate immune system.

Expression and characterization of an epididymis-specific gene

A truncated cDNA coding a rabbit epididymal protein (BE-20) was identified in a previous study. In the present study the full-length cDNA was isolated by the method of rapid amplification of cDNA ends. The BE-20 cDNA consisted of 585 bp with a poly(A) tail of 26 residues and an open reading frame composed of 369 bp encoding a deduced polypeptide containing 123 amino acid residues with a calculated molecular mass of 13 kDa. The N-terminus-contained a leucine-rich segment. BE-20 cDNA has about 76.8% homology with the HE4 gene of human epididymis. Northern blot analysis of mRNAs prepared from 17 different human tissues was performed using as probe a 0.5-kb DNA fragment corresponding to a segment of BE-20 cDNA. Positive reaction was elicited only with epididymal mRNA. A DNA fragment corresponding to a section of the open reading frame of BE-20 cDNA was cloned in Escherichia coli under the control of the T7 promoter. The cellular content of the expressed recombinant protein comprised about 55% of the total protein. The chromatographically purified bacterial product migrated as a single band with an estimated M(r) of 15 kDa on analysis by SDS-PAGE. In conclusion, BE-20 cDNA is expressed only in the epididymis. It is structurally related to the four-disulfide core family of extracellular proteinase inhibitors and may be involved in sperm maturation.

Equine CRISP-3: primary structure and expression in the male genital tract

Although originally described in the male rodent genital tract, cysteine-rich secretory proteins (CRISPs) are expressed in a variety of mammalian tissue and cell types. The proteins of the male genital tract have been observed associated to spermatozoa and are believed to play a role in mammalian fertilization. Here we describe the identification and primary structure of the first equine member of the CRISP family. Equine CRISP-3 is transcribed and expressed in the stallion salivary gland, in the ampulla and the seminal vesicle. It displays all 16 conserved cysteine residues and shows 82% homology to human and 78% to guinea pig CRISP-2 (AA1, TPX 1) and 77% to human CRISP-3. In contrast to other mammalia, in the horse CRISP-3 is synthesized in great amounts in the accessory sexual glands, ampulla and seminal vesicle, thus allowing the isolation of equine CRISP-3 in amounts suitable for biochemical, physiological and structural studies from stallion seminal plasma.

Differential androgen regulation of the murine genes for cysteine-rich secretory proteins (CRISP)

The androgen dependency of the genes coding for the cysteine-rich secretory proteins (CRISP) was analysed in their main sites of expression. Male mice were treated with the gonadotropin-releasing hormone antagonist Ac-DNapAla-DClPhAla-DPyrAla-Ser-Tyr-DCtl-Leu-Lys (Mor)-Pro-DAla-NH2 [DNapAla, D-2-naphthyl-Ala; DClPhAla, D-4-chlorphenyl-Ala; DPyrAla, D-pyridyn-3-yl-Ala; DCtl, D-citrulline; Lys(Mor), L-2-amino-6-(morpholin-4-yl)-hexanoic acid], and CRISP RNA levels were assessed by northern blot and competitive reverse transcriptase-mediated (RT)-PCR. In the salivary gland, CRISP-1 and to a lesser extent CRISP-3 expression was markedly reduced, in spite of an up-regulation of androgen receptor transcript levels. A down-regulation of CRISP-1 expression was also observed in the epididymis. Conversely, the levels of the testicular CRISP-2 transcripts were hardly affected at all. Female mice were ovariectomised and treated with testosterone propionate, and their salivary gland RNAs analysed. CRISP-1 and CRISP-3 RNA levels were significantly increased, and these effects were prevented by a concomitant treatment with the antiandrogen flutamide. Androgen receptor transcript levels were not affected by androgen administration but increased following antiandrogen treatment. CRISP expression during postnatal development was monitored by northern blot analysis. CRISP-1 and CRISP-2 transcripts were detected as early as 22 days after birth in the epididymis and testis, respectively, whereas CRISP-3 mRNA was visible only from day 30 in the salivary gland. A sharp increase of all CRISP levels was noted on day 40, coincident with the onset of sexual maturity. Altogether these results indicate that despite their high similarity, the CRISP genes are differentially regulated by androgens.

Recent advances in andrology research: physiopathology and clinical application to fertility and infertility

Sperm maturation depends on androgen and is mediated by several unidentified epididymal factors: glycoproteins and metabolites affecting acrosomal stability and fertilizing potential of capacitated sperm. Several genes encoding human epididymis-specific proteins have been described. One of the cloned epididymal cDNA encodes a polypeptide designated as HE4 with an estimated molecular mass of 10,000. Leydig cells are rich in lipid droplets and display epithelioid features. These cells have a cord-like arrangement; the cords are formed by one or two closely apposed cells. In between these cells, labyrinthine or canalicular-like spaces are opened in wide perivascular spaces that improve cell secretion of hormones and facilitate their transport into the blood, as well as the traffic of fluids and metabolites. Coagulation and liquefaction in human semen plays an important role in the capacitation of semen. The liquefaction of semen is retarded by the powerful synthetic inhibitors of 6-amidino-2-naphtyl-p-guanidinobenzoate dimethansulfonate.

Binding of rat and ovine epididymis-specific prealbumins (PES) to rat spermatozoa without effect of heterologous immunization on rat fertility

The epididymis, under control of testosterone, secretes proteins which bind to the membrane of the spermatozoa during their passage through the lumen. One such class is termed PES (prealbumin epididymal specific). Injection of heterologous oPES (ovine PES) into male rats caused antibody production but failed to induce sterility, unlike results previously obtained when rat PES was injected into male rats. This suggests that only very restricted species-specific epitopes of PES might be useful for causing immunocontraception. Despite this, the sperm binding properties of PES purified from the rat (rat PES) and from the ram (oPES) were shown to be similar. When either rat PES or oPES, conjugated with a fluorescent probe (dimethylamino-fluorescein), was incubated with washed rat spermatozoa originating from the caput, corpus or cauda epididymis, results of flow cytometric analysis showed: (1) the number of spermatozoa bound to isologous or heterologous fluorescent PES, and (2) the binding-affinity of spermatozoa for PES was greater for sperm collected from more distal sites in the epididymis.

Cloning of a human epididymis-specific mRNA, HE6, encoding a novel member of the seven transmembrane-domain receptor superfamily

A novel gene product, HE6, showing homology to the seven transmembrane-domain (Tm7) receptor superfamily, has been cloned by differential screening from a human epididymal cDNA library. The cDNA clone represented an abundant approximately 5-kb mRNA, comprising 0.01% of the cDNA library. Northern blot analysis including various human tissues revealed an epididymis-specific expression. In situ transcript hybridization localized the mRNA within the epithelial cells lining the epididymal duct. Southern blot analysis, employing a fragment encoding part of the amino-terminal extracellular domain as a probe, identified an autosomal single-copy gene in the human genome. Homologous cDNA products showing 90% sequence identity were observed in the epididymides of all mammalian species investigated. A cloning and sequencing strategy, combining approximately 3.7-kb cDNA fragments obtained by conventional cDNA library construction with overlapping 5' rapid amplification of cDNA ends (RACE) fragments, yielded total sequence information of 4.7 kb for the human mRNA. This sequence comprises a long open reading frame of 3.1 kb. A homology search for related sequences revealed highest similarity (25% amino acid identity) with the secretin/vasoactive intestinal peptide (VIP) superfamily of G-protein-coupled receptors. The predicted extracellular amino-terminal extension, however, was much longer than in the other members, and showed similarity to highly glycosylated mucin-like cell-surface molecules.

The 26 kD protein recognized on rat cauda epididymal sperm by monoclonal antibody 4E9 has internal peptide sequence that is identical to the secreted form of epididymal protein E

MAb 4E9, raised against a detergent extract of rat cauda epididymal sperm, recognizes a 26 kD glycoprotein that is found on the plasma membrane of the sperm tail in cauda, but not caput, sperm (Moore et al., 1994). It also recognizes an epididymis-secreted protein that has been shown to be protein E (Xu and Hamilton, 1996). It is felt that the secreted protein becomes associated with sperm, but there has been no biochemical evidence of molecular identity between the secreted and membrane proteins. In this report, the membrane form of the antigen has been purified by reverse phase HPLC. Cyanogen bromide cleavage of the purified protein yielded 3 peptides that were purified, also by reverse phase HPLC. One of the peptides yielded an unambiguous sequence of 34 amino acids that is identical to an internal peptide of the protein found in epididymal fluid. This is the first report showing sequence identity between an epididymis-secreted protein and a protein of the sperm plasma membrane.

Isolation and characterization of the androgen-dependent mouse cysteine-rich secretory protein-1 (CRISP-1) gene

In mice, cysteine-rich secretory protein-1 (CRISP-1) is mainly found in the epididymis and also, to a lesser extent, in the salivary gland of males, where androgens control its expression. We have now isolated and characterized overlapping phage clones covering the entire length of the CRISP-1 gene. DNA sequencing revealed that the gene is organized into eight exons, ranging between 55 and 748 bp in size, and seven introns. All exon-intron junctions conformed to the GT/AG rule established for eukaryotic genes. The intron length, as determined by PCR, varied between 1.05 and 4.0 kb so that the CRISP-1 gene spans over 20 kb of the mouse genome. The transcription-initiation site was determined by primer extension and localized at the expected distance downstream of a consensus TATA box. Approximately 3.7 kb of the CRISP-1 promoter region were isolated and sequenced, and several stretches fitting the androgen-responsive element consensus were found. Those that most resembled the consensus were analysed by electrophoretic mobility-shift assay and found to form specific complexes with the liganded androgen receptor in vitro, but with different affinities. Putative binding elements for the transcription factors Oct, GATA, PEA3, CF1. AP-1 and AP-3 were also found in the promoter region.

Expression of the BE-20 epididymal protein gene: in situ hybridization

A protein designated as BE-20 was purified from cauda epididymal fluid of male rabbits and the amino acid sequence of the N-terminus was determined. A 23-mer oligonucleotide coding the N-terminal eight amino acids of the BE-20 protein was synthesized. The oligonucleotide was used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. Digoxigenin-labeled BE-20 cDNA was prepared and used as a hybridization probe to detect the specific mRNA. The probe interacted with a 1.2-kb mRNA prepared from rabbit epididymis; mRNAs prepared from rabbit testis gave negative reaction. Using tissue sections, the BE-20 mRNA was located in the epithelial cells of the cauda epididymis and proximal segment of the ductus deferens by in situ hybridization method. Sections of the corpus and caput epididymis, testis, and liver gave negative reaction. Polyclonal anti-BE-20 antibodies were raised and found to inhibit in vitro the capacity of human sperm to penetrate zona-free hamster ova. The results suggest that BE-20 protein may influence maturation of spermatozoa during its movement through the epididymis and/or the capacity of sperm to fertilize ova.

Identification of a rabbit epididymal protein gene

A protein designated as BE-20 was purified from cauda epididymal fluid of the rabbit by preparative polyacrylamide gel electrophoresis and HPLC on a mono Q HR5/5 anion exchange column. The purified protein migrated with an estimated Mt of 20,000 when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The amino acid sequence of the N-terminus of the BE-20 protein was determined. The initial eight amino acid residues were His-Gly-Ala-Asp-Lys-Pro-Gly-Val. The corresponding 23 mer oligonucleotide (5'-CATGGCGCTGACAAGCCTGGGGT-3') was synthesized and used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The purified BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. The BE-20 cDNA had 78.5% identity in 479 bp overlap with human epididymis-specific HE4 cDNA. The amino acid sequences of the initial 30 amino acid residues of the N-terminus of the purified protein and the deduced polypeptides were as follows: N-His-Gly-Ala-Asp-Lys-Pro-Gly-Val-Cys-Pro-Gln-Leu-Ser-Ala-Asp-Leu-Asn-Cy s- Thr-Gln-Asp-Cys-Arg-Ala-Asp-Gln-Asp-Cys-Ala-Glu. The deduced polypeptide contained 16 cysteine residues and had partial sequence homology with proteins belonging to the four-disulfide core family of extracellular proteinase inhibitors. The BE-20 protein may play a role in sperm maturation and/or capacitation.

The human cysteine-rich secretory protein (CRISP) family. Primary structure and tissue distribution of CRISP-1, CRISP-2 and CRISP-3

We report the isolation and characterisation of cDNAs encoding three different, human members of the cysteine-rich secretory protein (CRISP) family. The novel CRISP-1 exists in five cDNA subtypes differing by the presence or absence of a stretch coding for a C-terminal cysteine-rich domain so far found in all members of the family, and by the length of their 3'-untranslated region. CRISP-2 cDNA corresponds to the previously described TPX1 form, with so far unreported 5'-untranslated sequence heterogeneities while CRISP-3 cDNA codes for a new, unique protein. Northern blot analysis of various human organs indicates that CRISP-1 transcripts are epididymis-specific whereas CRISP-2/TPX1 transcripts are detected mainly in the testis and also in the epididymis. CRISP-3 transcripts are more widely distributed and found predominantly in the salivary gland, pancreas and prostate, and in less abundance in the epididymis, ovary, thymus and colon. A protein reacting with an anti-mouse CRISP-1 antibody was isolated from human epididymal extracts and N-terminal sequencing revealed that it corresponded to the CRISP-1 cDNA we have isolated. In contrast to findings on its rat counterpart epididymal protein DE/acidic epididymal glycoprotein (AEG), no significant association of CRISP-1 with human spermatozoa was observed.

Identification of the rat epididymis-secreted 4E9 antigen as protein E: further biochemical characterization of the highly homologous epididymal secretory proteins D and E

Epididymis-secreted proteins D and E have been purified to homogeneity and partially characterized, and it is shown that monoclonal antibody (MAb) 4E9 (raised against a detergent extract of rat caudal epididymal sperm [Moore et al., 1994: Mol Reprod Dev 37(2):181-194]) recognizes protein E, but not protein D. The molecular weight of protein D (approximately 30 kD) is approximately 2 kD lower than protein E (approximately 32 kD). The NH2-terminus of each protein is blocked; however, microsequencing of internal peptides confirms earlier reports of significant sequence identity between the two proteins. High performance liquid chromatography tryptic peptide mapping showed peak differences between the two proteins, but it was not possible to obtain amino acid sequence in the peaks that were different. The epitope for MAb 4E9 was localized in the blocked NH2-terminus-CNBr peptide derived from protein E. The epitope was destroyed by protease treatment of protein E. Removal of N-linked oligosaccharides did not destroy the epitope for MAb 4E9 and did not affect the molecular weight difference between the proteins.

Mouse androgen-dependent epididymal glycoprotein CRISP-1 (DE/AEG): isolation, biochemical characterization, and expression in recombinant form

In the rat, the secretory glycoprotein DE/AEG is one of the main constituents of the epididymal fluid. We have recently reported the cloning of the cDNA for the related cysteine-rich secretory protein-1 (CRISP-1) from murine epididymis (Haendler et al., 1993; Endocrinology 133:192-198). The protein has now been isolated from the same organ and its N-terminal amino acid sequence has been determined. CRISP-1 exhibited an isoelectric point of approximately 6.8. High levels of CRISP-1 antigen were detected in the corpus and cauda of the epididymis, vas deferens, seminal vesicle, prostate, and in the salivary gland by immunohistochemistry. A quantitative analysis of the cauda epididymal fluid by sandwich ELISA revealed that CRISP-1 represented approximately 15% of the total protein. For heterologous expression, the CRISP-1 coding sequence was introduced into the pMPSV/CMV vector before transfection of baby hamster kidney (BHK) cells and selection with puromycin and neomycin. Expression in insect cells was achieved by co-transfection of Sf9 cells with a transfer vector and baculovirus DNA. Recombinant CRISP-1 was isolated in quantities sufficient for structural analysis. Ethyl maleimide treatment showed that all 16 cysteines were engaged in disulfide bonds. Proteolytic digestion demonstrated that the six cysteines localized in the N-terminal moiety formed three bonds with each other, suggesting the existence of two discrete domains in the protein.

Isolation and characterization of the androgen-dependent mouse cysteine-rich secretory protein-3 (CRISP-3) gene

The mRNA for cysteine-rich secretory protein-3 (CRISP-3) was originally identified in the mouse salivary gland as an androgen-dependent transcript, and is closely related to CRISP-1 and CRISP-2 which are abundantly expressed in the epididymis and testis respectively. Overlapping phage clones encompassing the entire length of the CRISP-3 gene were isolated from a lambda EMBL3 genomic library and analysed. DNA sequencing revealed that the gene consisted of eight exons ranging between 55 and 740 bp in size, and seven introns. All exon-intron junctions conformed to the GT/AG rule established for eukaryotic genes. The length of the introns was determined by PCR and was found to vary between 1.0 and 3.7 kb, indicating that the gene spans over 20 kb of the mouse genome. Primer extension allowed the mapping of the major transcription initiation site to an adenine located at the appropriate position downstream of a bona fide TATA box, in a region corresponding well to the eukaryotic consensus sequence. Over 800 bp of CRISP-3 promoter region were determined and two regions almost exactly matching the androgen-responsive element consensus RGWACANNNTGTWCY detected. In addition, sequences described in the Drosophila melanogaster Sgs-3 gene as being involved in its salivary gland-specific expression as well as two putative OTF- and GATA-binding elements were also found.

Electron microscopic immunolocalization of the 18 and 29 kilodalton secretory proteins in the mouse epididymis: evidence for differential uptake by clear cells

In previous studies we reported the synthesis, secretion, and immunolocalization at the light microscopic level of two mouse epididymal proteins, MEP 7 and MEP 10 [Rankin et al. (1992b), Biol. Reprod., 46:747-766]. MEP 7 is the mouse homologue of the rat metalloproteins, AEG/D and E, and MEP 10 is the mouse homologue of the rat retinoic acid binding proteins, B and C. We now describe the immunolocalization of MEP 7 and MEP 10 in the mouse epididymis at the electron microscopic level. MEP 7 was localized in the Golgi apparatus, in small electron-lucent secretory vesicles, and on microvilli of the principal cells from the distal caput epididymidis to the cauda. The luminal contents were also immunoreactive in these regions of the epididymis. Although some gold particles were associated with the sperm surface, there was no selective concentration of these particles. In addition, MEP 7 was localized in large (600 nm) supranuclear endocytic vesicles and in infranuclear lysosomes. MEP 10 immunoreactivity was also seen on the microvilli of the principal cells of the distal caput and corpus and the luminal contents from the distal caput to the cauda epididymidis. There was no association of gold particles with the sperm surface. In contrast to MEP 7, there was no detectable MEP 10 immunoreactivity on the organelles of the principal cells involved in protein secretion or endocytosis. Clear cells also demonstrated immunoreactivity to MEP 7 and MEP 10. However, the intensity of immunolabeling, and the number of clear cells labeled, was greater with MEP 10 than MEP 7. In the case of MEP 7, the gold particles were located on the large supranuclear endocytic vesicles and on some infranuclear lysosomes, from the proximal corpus to the middle cauda, while in the case of MEP 10, gold particles were predominantly present in infranuclear lysosomes from the distal caput to the middle cauda. These results suggest that the principal cells are involved in both the secretion and endocytosis of MEP 7. The MEP 10 and MEP 7 proteins present in the lumen of the mouse epididymis are endocytosed from the lumen and degraded in the clear cells. However, the process of endocytosis by the clear cells of these two proteins appears to be different.

Two Golgi integral membrane proteins (GIMPS) exhibit region- and cell type-specific distribution in the epididymis of the adult rat

The epididymis participates in the post-testicular maturation and storage of spermatozoa by secreting proteins into the tubule lumen in a region-specific fashion. The underlying molecular mechanisms leading to biogenesis of these region-specific differences, however, are not known, although components of the Golgi complex membrane container must undoubtedly be intimately involved. Two monoclonal antibodies raised against Golgi integral membrane proteins, recognizing either the cis (GIMPc) or trans Golgi (GIMPt) cisternae, were used as molecular probes of these regions to begin the characterization of the Golgi complex of in vivo and in vitro epididymal cells. Immunolocalization of GIMPs was performed on frozen sections and in cultured cells using biotin-streptavidin-peroxidase immunocytochemistry. In tissue sections, immunostaining of GIMPt was extremely robust in the supranuclear cytoplasm throughout the epididymis. In contrast, no GIMPc immunostaining was detected in the initial segment or in clear cells of the distal caput, corpus, and cauda. Immunodetection of GIMPc and GIMPt in epididymal cells in vitro revealed a reticular, perinuclear pattern, and NH4Cl treatment preferentially disrupted the GIMPt immunolocalization. These results characterizing the molecular components of the Golgi complex will form the basis of additional studies to gain further insight into mechanisms leading to generation of regional differences in epididymal function.

Regional variation of specific gene expression in the dog epididymis as revealed by in-situ transcript hybridization

In-situ transcript hybridization was used to characterize the regional distribution of three marker gene transcripts which are expressed abundantly in the canine epididymis. The gene products CE1, CE4 and CE5, which are the canine equivalents of the human homologues HE1, HE4 and HE5, are shown to be expressed in a tissue-specific and regionally characteristic pattern in the epididymal epithelium. CE1 mRNA was expressed very weakly in the efferent ducts but was expressed at a high level throughout the caput and corpus regions of the epididymis, decreasing somewhat in the distal cauda region. CE4 mRNA was not detectable in the efferent ducts and was only expressed moderately in the remainder of the epididymis, with greatest levels in the caput and proximal cauda regions, and decreasing in the distal cauda. CE5 mRNA showed the most marked regional variation in levels with little or no mRNA detectable in the caput and proximal corpus regions, but increasing dramatically in the distal corpus and cauda. In the transition region of the central corpus, the CE5 mRNA appeared to be expressed intermittently, giving a mottled signal appearance over the epididymal epithelium. The patterns of mRNA distribution for the three marker genes in the dog epididymis were, therefore, essentially similar to those for the equivalent human homologues, providing further support for the suitability of the dog epididymis as a model for the human.

Mouse submandibular glands express an androgen-regulated transcript encoding an acidic epididymal glycoprotein-like molecule

Acidic epididymal glycoprotein (AEG) is an androgen-regulated, epididymal secretory protein assumed to be involved in sperm maturation. In the present study, we show that the mouse submandibular gland (SMG) expresses two genes designated Aeg-1 and Aeg-2. The nucleotide sequence of Aeg-1 cDNA clones was identical to that of epididymis-expressed Aeg cDNA clones, indicating that Aeg-1 is expressed in both epididymides and SMGs. The second, more abundant transcript, Aeg-2, had a sequence similar to, but distinct from, that of Aeg-1, and was not detectable in the epididymis. The level of Aeg-1 and Aeg-2 transcripts in the SMG was androgen-regulated and showed sexual dimorphism. In situ hybridization of SMG sections showed that Aeg-1 and Aeg-2 transcripts are produced by the cells of granular convoluted tubules. The C-terminal cysteine-rich region of the mouse AEG-2 molecule appears to have diverged faster than that of the mouse AEG-1 molecule, consistent with the idea that this region may play a role unique to the protein of the male reproductive system.

Differential patterns of regulated gene expression in the adult rat epididymis

Specialization among the principal epithelial cells of the epididymal tubule is documented following the analysis of transcriptional activity of four distinct species of mRNA. In situ histochemical analysis revealed a unique pattern of expression for each transcript. This observation supports the concept that region-specific patterns of transcriptional expression along the epididymal tubule serve as the major molecular basis underlying region-specific patterns of luminal proteins within the tubule. Additionally, multiple testicular factors appear to regulate expression of these mRNAs. The transcript encoding peptidyl-prolyl cis-trans isomerase is constitutively expressed. Those encoding the major secretory proteins, protein B/C and protein D/E, are directly regulated by testicular androgen. That encoding the opioid peptide precursor, proenkephalin, is regulated by a non-androgen testicular factor(s), specifically, spermatozoa or a spermatozoa-related factor. Thus, a complex array of nuclear events and signals received by the principal cells serve to determine the transcriptional status of genes expressed within this epididymal cell type.

Opposite variations of two epididymal components and blood plasma testosterone in two breeds of rams

1. Testicular volume (T Vol), blood plasma testosterone (T) concentration, seminal plasma alpha-glucosidase (alpha-G) specific activity, L-carnitine (L-C) concentration as well as semen characteristics were compared in eight Finnish Landrace (F) and eight Suffolk (S) rams throughout 21 months. 2. Only T Vol and T exhibited a typical seasonal variation in both breeds, whereas L-C, alpha-G and live sperm output presented a seasonal profile only in S rams. 3. L-C and alpha-G variations were opposite to those of T in S rams, while they fluctuated in F rams throughout the entire experiment, as did live sperm output. 4. Only the number of ejaculates and T were significantly higher in F rams (3.50 +/- 0.08 in 5 min and 7.62 +/- 0.40 ng/ml) than in S rams (2.30 +/- 0.05 in 5 min and 5.5 +/- 0.30 ng/ml); these two characteristics might therefore be considered as two indexes of sexual activity in rams. 5. By contrast, among all characteristics measured, only alpha-G was significantly higher in S rams than in F rams (1.33 +/- 0.04 vs 0.77 +/- 0.03 mU/mg proteins); this result, as well as seasonal alpha-G profile present in only S rams, allowed us to conclude that alpha-G might be considered as an additional index of seasonal reproduction in rams.

The delivery of testosterone and dihydrotestosterone by ALCAP ceramic implants in rats

The objectives of this investigation were to evaluate the release of testosterone (T) and dihydrotestosterone (DHT) from nonimpregnated and polylactic acid (PLA) impregnated ALCAP ceramic reservoirs implanted in rats, and to study the effects of delivered androgens on the reproductive system of male rats. A total of 120 Sprague-Dawley albino male rats were distributed equally into three groups Two ALCAP capsules, one nonimpregnated and the other impregnated with PLA, were implanted into each rat in groups I and II. Capsules implanted into group I rats were loaded with a mixture of 20 mg T and 20 mg DHT. Group II rats were implanted with two empty capsules (sham group), and group III animals served as unimplanted controls. Eight rats from each group were euthanized at the end of 3, 6, 9, and 12 months following the implantation of the ceramics. No significant change in the weights of vital organs of rats was observed among any of the three different groups. Vas deferens and epididymal fluid were devoid of normal spermatozoa within 3 months of implanting the steroid-containing ceramics. Testicular weights decreased significantly in the rats implanted with ALCAP containing steroids and the seminiferous tubules became oligospermic after 1 month and azoospermic after 3 months. The data collected in this study suggest that (1) ALCAP ceramic capsules are capable of delivering T and DHT in combined form, and (2) T and DHT delivered by ALCAP capsules can be used effectively to regulate spermatogenesis in rats.